The prime focus of this study is to determine the mechanism of biosynthesis of the oligosaccharide portion of asparagine-linked membrane glycoproteins of aorta, and also to elucidate the structures and functions of these glycoproteins. Working with detergent-solubilized, particular enzyme preparations from aorta, the lipid-linked product, Man5GlcNAc2-pyrophosphoryl-dolichol has been isolated. On the basis of several lines of evidence we have concluded that the mannose residues for the above oligosaccharide lipid come directly from GDP-mannose rather than the mannose-linked lipid. We are currently accumulating large amounts of Man5GlcNAc2 as well as other smaller oligosaccharide intermediates for complete structual characterization via methylation and mass spectrometric analyses. Further purification of the solubilized mannosyl transferases is also underway and the functional signficance of cell surface glycoproteins is being studied using a system of adherence of bacteria to mammalian cells. The antibiotics tunicamycin and streptiovirudin were fractionated using high performance liquid chromatography, and the various fractions were assayed for inhibiting activity. The more hydrophobic tunicamycins were generally more inhibitory. Series I and II streptovirudins differed in that the former was found to contain dihydrouracil in place of uracil. The effects of tunicamycin and streptovirudin fractions on the synthesis of lipid-linked saccharides will also be examined both in vivo and in vitro. In addition a number of other antibiotics will be studied for specific inhibition of the lipid-linked pathway.